October 2010 to September 2011 was the driest year on record in central Texas, with only 11.2 inches of rain—about one-third of the 33-inch average. It also had the hottest summer since record keeping began in 1860, with 89 days hotter than 100°F. All this puts further strain on the already-stressed Edwards Aquifer. Aquifer replenishment is further hampered because rainfall now often occurs in larger bursts, rather than slower trickles—creating runoff and flash floods instead of recharging the aquifer.
Drought and heavy rainfall events also make living with a rainwater collection system like Nancy’s more complicated. Nancy’s system has a total of 6,200 gallons of storage, and for five years this was plenty. But the drought forced her to hire a water service company to fill her auxiliary tank with 1,200 gallons of water each month during the summer—just enough, if she scrimped, to get by.
Sizing your water storage system for “extreme” events, such as historic droughts, can be very difficult. It’s often a give and take between the willingness of the homeowner to sacrifice their independence in times of extreme weather and the significant cost of much-larger storage systems. At $75 per month for trucked-in water, it wouldn’t take too many similar summers to make it cheaper to have installed a larger tank at the outset, with additional storage in a larger tank costing about $0.50 per gallon at this size.
Rainwater catchment improves aquifer replenishment—heavy rains are caught by the catchment system and stored, and then released slowly into the ground as it passes through the household and septic system. Some of this groundwater flows into nearby streams, but much leaches into the aquifer. Nancy can take satisfaction that her home has gone from an impervious surface that contributes to runoff, to a building that helps rainwater percolate down to the water table.